public void FlashKeep()
{
Flash flash = new Flash();
flash.Now("test1","hello");
flash.Now("test2","hello");
flash.Keep("test1");
flash.Sweep();
Assert.IsTrue( flash.ContainsKey("test1") );
Assert.IsFalse( flash.ContainsKey("test2") );
flash = new Flash(flash);
flash.Sweep();
Assert.IsTrue( flash.Count == 0 );
flash.Now("test1","hello");
flash.Now("test2","hello");
flash.Keep();
flash.Sweep();
Assert.IsTrue( flash.ContainsKey("test1") );
Assert.IsTrue( flash.ContainsKey("test2") );
}